ANTHOMEDUS^E SLABBERIA. 77 



proximal part of the manubrium, and finally at the distal end a long, club-shaped, cylindrical 

 region, at the extremity of which the mouth is situated. The 2 genital organs are found 

 within the 2 swollen regions of the manubrium. The color of these medusae is quite variable, 

 the entoderm of the manubrium and tentacles being either yellow, or yellow and red, or red, 

 or green and red. In the young medusas the entoderm of the manubrium is usually yellow, and 

 of the tentacles yellow dotted with red granulations; while in the mature medusa the color 

 of the entoderm is usually green or yellowish-green. 



Young medusa (plate 7, fig. 3). In the youngest medusa observed, the bell is cylindrical 

 with vertical sides and a slight apical projection. The gelatinous substance is thin. There are 

 2 diametrically opposed tentacles each of which terminates in a single, large, nematocyst- 

 covered knob. The other 2 tentacles are as yet undeveloped and are represented by mere 

 basal bulbs. There are 4 ocelli, one upon each basal bulb. The manubrium is a simple, short, 

 conical tube and the mouth is a simple, round opening. 



When the medusa is I mm. in height, a constriction appears near the proximal end of the 

 manubrium, which thus becomes divided into an upper and lower swollen region. As develop- 

 ment proceeds this constriction becomes more marked and finally the manubrium assumes 

 the adult shape; the upper and lower swellings of the young proboscis corresponding to the two 

 swollen regions of the manubrium of the adult medusa. Hargitt, 1904, describes the young 

 medusa under the name of "Dtpurella clavata." 



This medusa is exceedingly abundant in August and September in Charleston Harbor, 

 South Carolina. It has been found by Brooks at Beaufort, North Carolina; and by A. 

 Agassiz and Verrill in Buzzards' Bay, Massachusetts. It has not been taken north of Cape 

 Cod, Massachusetts, and has not been observed at the Tortugas, Florida. 



Slabberia strangulata var. fragilis. 

 Plate 7, fig- 4- 



Difurena fragilis, MAYER, 1900, Bull. Mus. Comp. Zool. at Harvard College, vol. 37, p. 29, plate 17, fig. 41. 

 (?) Difurena fragilis, BIGELOW, 1904, Bull. Mus. Comp. Zool. at Harvard College, vol. 39, p. 251. 



Bell 4 mm. high and halt-egg-shaped, with moderately thick walls, becoming thinner 

 near the margin. There are 4 long, slender tentacles, each about as long as the bell-height. 

 These terminate each in a single knob armed with nematocysts. The tentacle-bulbs upon 

 the bell-margin are not large, but each one bears a single, black ocellus in the ectoderm of its 

 outer side. Velum wide. There are 4 straight, narrow radial-canals and a slender, circular 

 vessel. Manubrium about twice as long as bell is high. It is slender and tubular, with two 

 separate, swollen regions containing the gonads. The entoderm of the manubrium and of 

 the basal bulbs of the tentacles is dull yellow, while the entoderm of the terminal knobs of 

 the tentacle is a faint orange. 



This variety is found at Tortugas, Florida, in June. Bigelow, 1904, found a colorless 

 Dipurcna at Suvadiva Atoll, Maldive Islands, Indian Ocean, which he believes is probably 

 identical with Dipurena fragilis. 



S. fragilis may be distinguished from other American Dipurenae by its \ong,very slender 

 tentacles, and the dull-yellow color of its entoderm. 



Slabberia catenata Forbes and Goodsir. 



Plate 8, figs. 8 and 9. 



Slabberia catenata, FORBES and GOODSIR, 1853, Trans. Roy. Soc. Edinburgh, vol. 20, p. 311, plate 10, figs. ya-^e. 



Difurena dolichogaster, HAECKEL, 1864, Jena. Zeltschrift fur Naturw., Bd. i, p. 337; 1879, Syst. der Medusen, p. 25, taf. 2, 



figs. 1-7. 



Difurena calenata, HAECKEL, 1880, Syst. der Medusen, p. 655. 



Difurena fertilis, METSCHNIKOFF, E. and L., 1870, Verhandl. Gesell. Freunde Nat. Moskau, tome 8, p. 343, taf. 3, figs. 1-5. 

 Sarsia dolichogaster, SPAGNOLINI, 1876, Catalogo Acalefi Mediterraneo, p. 18, tav. 2, fig. 3 (from Naples, Italy). 

 Difurena dolichogaster, CHUN, 1895, Bibliotheca Zoologica, Heft 19, p. 6, taf. i, figs. 1-4. * 

 Difurena catenata, MONTICELLI, 1897, Atti Accad. Sci. Torino, vol. 32, p. 888, I fig. (abnormal specimen from the Gulf of 



Cagliari, with a manubrium which gives off 2 side branches, each with mouth and gonad). 

 ( ?) Sarsia clavata, KEFERSTEIN, 1862, Zeitschrift fur wissen. Zool., Bd. 12, p. 27, taf. 2, figs, i, 2. 

 ( ?) Sarsia, sp., ALLMAN, 1871, Monog. Tubul. Hydroids, p. 83, fig. 37. 

 (?) Sarsia clavata, HAECKEL, 1879, Syst. der Medusen, p. 19. 



( ?) Sarsia clavata (Syncoryne clavata), GRAEFFE, 1884, Arbeit. Zool. Inst. \Vien, Bd. 5, p. 351 (first description of the hydroid). 

 Difurena ficta, MAYER, 1900, Bull. Mus. Comp. Zool. at Harvard College, vol. 37, p. 29, plate 18, figs. 45, 46. 

 (? Sarsia clavala)^ Slabberia catenata, HARTLAUB, 1907, Nordisches Plankton, Nr. 12, pp. 51, 63, figs. 46, 59. 



